1. Field of the Invention
The present invention relates to an etching process method.
2. Description of the Related Art
Techniques are known for etching a silicon-containing film using a halogen-based gas (see e.g., Published Japanese Translation of PCT International Application No. 2010-500758). On the other hand, by using a hydrocarbon-based (CH-based) gas, such as CH4 (methane) gas or CH2F2 (difluoromethane) gas, to etch a silicon-containing film, mask selectivity can be increased. For this reason, it is beneficial to use a hydrocarbon-based gas in etching a deep hole or a deep trench having a high aspect ratio, for example.
However, because a hydrocarbon-based gas is a depositing gas, when the amount of hydrocarbon-based gas used is increased, particles may adhere to an opening in a mask and clog the opening to thereby make etching difficult, for example. Also, the surface of the mask may roughen, and the etching profile of a hole formed in the silicon-containing film may be degraded, for example.